Sickness behaviour reduces network centrality in wild vampire bats

Simon P Ripperger; Sebastian Stockmaier; Gerald G Carter

Indeed, LPS-induced sickness behaviour caused a dramatic decrease in network 58 centrality. The control bats encountered fewer 'sick' individuals and also spent less time near 59 them. For studying pathogen transmission, the links (or edges) in a social network would ideally 60 be defined based on the pathogen-specific transmission mechanism, because some pathogens 61 require longer or closer physical contact. In practice, however, most social network edges are 62 . We captured bats from a colony of common vampire bats (Desmodus rotundus) inside a 70 hollow tree at Lamanai, Belize. Before sunset on April 24 th 2018, we blocked all exits of the 71 roost except one and we used a handnet and mist nets to capture about 100 vampire bats 72 (including 41 females) until 0500 h the next morning. We kept females in cotton cloth bags, and 73 measured their mass to ensure they did not differ between the randomly assigned treatment 74 and control injections (difference in mass = 0.17 g [95% CI: -2.9, 2.4]). We randomly assigned 75 the females to the test or control treatment by flipping a coin, then adjusted to ensure more 76 balanced samples. We injected the individuals in the test group under the dorsal skin with 70-77 100 µl of LPS (lipopolysaccharide in phosphate-buffered saline, L2630 Sigma-Aldrich, St Louis, 78 MO, U.S.A.) at a dosage of 5 mg/kg, following previous studies with this species [6, 7] . Bats in 79 the control group received an injection of the same volume per body mass of phosphate-80 buffered saline. One hour after injection, we released 34 females, tagged with proximity 81 sensors, back into their roost. 82 83